When it comes to video resolution, SD and 720p are two common terms that are often used. SD stands for “standard definition” while 720p refers to a specific resolution of 1280 x 720 pixels. This leads to the question – is SD 720p?
What is SD?
SD or standard definition refers to a lower quality video resolution that was widely used in older analog TV systems. The most common SD video resolutions are:
- 480i – 720 x 480 pixels (Used in NTSC countries like USA)
- 576i – 720 x 576 pixels (Used in PAL countries)
These resolutions have less than 1 million total pixels. The “i” stands for interlaced, which means the video signal displays alternate lines of the image in each refresh. So SD resolution is quite low compared to today’s high definition video.
What is 720p?
720p refers to a high definition video resolution with 720 horizontal lines of vertical resolution and a progressive scan display. The main HD resolutions are:
- 720p – 1280 x 720 pixels
- 1080p – 1920 x 1080 pixels
- 1440p – 2560 x 1440 pixels
- 2160p (4K) – 3840 x 2160 pixels
Of these, 720p has the lowest resolution but is still considered HD. The “p” stands for progressive scan, which displays the entire image at once instead of line-by-line like interlaced. 720p has over 900,000 total pixels, much greater than SD.
Is SD 720p?
Based on the above details, it is clear that SD and 720p refer to very different video resolutions. SD ranges from 720 x 480 to 720 x 576 pixels while 720p has a resolution of 1280 x 720 pixels. Some key differences:
| Resolution | SD | 720p |
|---|---|---|
| Pixels | 345,600 to 414,720 | 921,600 |
| Aspect Ratio | 4:3 | 16:9 |
| Display | Interlaced | Progressive |
Based on this comparison, it is evident that:
SD resolution ranges from 480i to 576i and has less than 1 million total pixels.
720p resolution is 1280 x 720 pixels and has over 900,000 pixels.
Therefore, SD and 720p are completely different video standards. SD is low resolution intended for old analog TVs while 720p is a high definition digital video format. Simply put, SD is not 720p. The two should not be used interchangeably when discussing video quality and resolution.
Uses of SD and 720p Video
Due to their very different resolutions, SD and 720p video are typically used in different applications:
SD Video Uses
- Older analog TV broadcasts
- VHS, Betamax, Video8 tapes
- DVD Video
- Early digital camcorders
- Video surveillance systems
SD continues to be used for some video distribution and recording purposes where high resolution is not critical. This includes things like security cameras, legacy video systems, and some streaming applications.
720p Video Uses
- HD broadcasting
- Blu-ray discs
- HD camcorders and DSLRs
- Smartphones and tablets
- Video game consoles
- Web video like YouTube
- Video conferencing and chat apps
720p strikes a good balance of resolution and bandwidth usage. It provides substantially better image quality than SD while keeping bandwidth requirements reasonable. This makes it a popular choice for streaming and real-time communication apps.
Video Quality Comparison
To see the difference in visual quality, here is a side-by-side comparison of an image in SD 480p vs 720p resolution:
| SD 480p Resolution | 720p Resolution |
When scaled to the same display size, the 720p image contains far more detail, sharper edges, and less pixelation. Fine details that are lost in the SD version are clearly visible in the 720p version. The higher pixel density makes the overall image quality significantly better.
Bitrate Differences
In addition to resolution, SD and 720p video also differ significantly in their bitrate. Bitrate refers to the amount of data used to store or transmit each second of video. A higher bitrate allows more detail and clarity:
| Video Type | Typical Bitrate Range |
|---|---|
| SD | 1 – 3 Mbps |
| 720p | 3 – 6 Mbps |
SD video has bitrates ranging from 1-3 Mbps usually, while 720p video is encoded at 3-6 Mbps depending on the application. This allows 720p footage to show finer details compared to SD at an equivalent bitrate.
Resolution vs. Bitrate
Is resolution or bitrate more important for video quality? This depends on the specific scenario:
- For stored/streamed video, resolution and bitrate are equally important. Resolution determines detail/clarity, bitrate determines encoding quality at that resolution.
- For real-time applications like video calls, resolution has more impact. Bitrate is limited by connection speed, so higher resolution improves quality.
Ideally, video should have both high resolution like 720p AND a high bitrate to maximize visual quality. But higher resolution can provide a benefit even at low bitrates in real-time and streaming uses.
Is 720p Noticeably Better Than SD?
There is no doubt that 720p offers a dramatically better viewing experience compared to SD. The higher resolution and bitrate allow a sharper, more detailed image. When comparing SD and 720p video side-by-side, the difference is very noticeable.
Some key factors that make 720p better than SD:
- Over twice the horizontal resolution (1280 vs 720 lines)
- Around 2X higher pixel density
- Higher bitrate provides more coding detail
- 16:9 widescreen aspect ratio vs 4:3 fullscreen
However, on very small screens like old mobile phones, 720p may not look visibly better than SD. But on any modern device with a screen larger than 5 inches, the difference is obvious. 720p provides sufficient resolution to see the advantage of HD video.
720p vs 1080p Comparison
Since 720p and 1080p are both HD resolutions, how do they compare in terms of quality? Some key differences:
| 720p | 1080p | |
|---|---|---|
| Resolution | 1280 x 720 | 1920 x 1080 |
| Pixel Count | 921,600 | 2,073,600 |
| Aspect Ratio | 16:9 | 16:9 |
As seen above, 1080p has around twice the total number of pixels as 720p, providing even greater detail and sharpness. However, on smaller screens like laptops and mobile devices, the visual benefit of 1080p over 720p may not be as noticeable.
720p continues to be popular for real-time streaming and communication apps due to its lower bandwidth requirements compared to 1080p. But for stored/offline video consumption like Blu-rays, 1080p offers the best quality.
Conclusion
SD refers to the low resolution 480i/576i video used in older analog systems while 720p is a high definition 1280 x 720 progressive scan digital video format. 720p has around twice the resolution and 2-3X higher bitrate compared to SD video.
The bottom line is that SD and 720p are very different video standards in terms of both resolution and quality. 720p is unquestionably superior to SD and enables an obviously sharper, more detailed viewing experience. Saying that SD equals 720p is completely inaccurate and misleading.
720p continues to be one of the most prevalent HD standards used in various applications from streaming video to HD broadcasting. While 1080p offers even greater resolution, 720p provides a noticeable quality boost from SD while keeping bandwidth manageable. Any claim that 720p provides the same quality as SD should be dismissed as false.